1. Field of the Invention
The invention relates to a vehicular automatic transmission. More particularly, the invention relates to an improvement for increasing the degree of freedom in structure of a hydraulic circuit and the like.
2. Description of Related Art
A stepped automatic transmission that is provided with a plurality of engagement elements, and selectively establishes a plurality of speeds according to an engagement/release combination of the plurality of engagement elements is widely used in a variety of types of vehicles. For the engagement elements, hydraulic friction engagement devices that are switched between an engaged state and released state by hydraulic pressure, for example, are used and a variety of structures have been proposed. For example, an automatic transmission described in Japanese Patent Application Publication No. 2011-017373 (JP 2011-017373 A) includes three planetary gear sets and six engagement elements, and is configured such that eight forward speeds (i.e., first speed to eighth speed) and one reverse speed are able to be selectively established by engaging any three of the six engagement elements and releasing the other three engagement elements.